The present disclosure relates to a gas turbine engine and, more particularly, to a flange arrangement for a case structure thereof.
One purpose of a gas turbine engine turbine exhaust case (TEC) is to support a bearing compartment and the bearings contained therein that rotatably support the engine shafts. Typically, the TEC includes a plurality of hollow struts which support a pair of concentric rings relative to each other. The rings define inner and outer boundaries of the engine gas path while the struts are disposed across the gas path. Tie rods support the bearing housing and pass through the hollow struts to interconnect an engine mount ring and the bearing compartment.
In some engine architectures, a two-bearing compartment locates a TEC case flange F1 adjacent to two bearing supports flanges F2, F3 to facilitate access to the bearing compartment without removal of the TEC case (FIG. 1). The case flange F1 wraps around the bearing support flanges F2, F3 which, although effective, may carry extra weight and concentrate low cycle fatigue (LCF) stresses in the case flange F1. One way to reduce these stresses to acceptable levels is to increase the thickness of the case flange F1 but this increases weight.